What is the device that indicates the flow of current through an electrical circuit?

The device that indicates the flow of current through an electrical circuit is a galvanometer, which is specifically designed to detect and measure small electrical currents. It functions by using a coil of wire placed in a magnetic field, where the current flowing through the coil causes it to move, allowing for a visual indication of the current flow.

While a multimeter is a versatile tool that can measure voltage, current, and resistance, it requires setting to the appropriate measurement type and is not exclusively an indicator of current flow. An oscilloscope, on the other hand, is used for visualizing electrical waveforms rather than directly measuring current. An ammeter measures current as well but is typically more focused on larger currents and often incorporates a galvanometer as part of its design. Therefore, the uniqueness of a galvanometer lies in its simplicity and specific function for current detection, making it the most accurate answer to the question.